Known as ‘the finest dining hall in Europe’, the Painted Hall in the Old Royal Naval College is covered from floor to ceiling with an elaborate visual narrative. Classical figures symbolising the triumph of peace over tyranny perch among British monarchs and depictions of naval power.

The painted walls took Sir James Thornhill 19 years to complete and when he finally finished, the building was far too grand for its original purpose as a dining hall for naval veterans. It became an attraction open only to respected visitors, for a small fee, and the veterans provided tours.

The oldest building on the Parliamentary estate, Westminster Hall has played a part in British life since it was built in the 11th century by William the Conqueror’s son. When you step inside, look up - its incredible double-hammerbeam roof is a marvel, and known as one of the most ingenious inventions of medieval carpentry.

While the hall boasts a stupendous size (1,547 square metres), what really cements the importance of the building is the sheer number of key historic events that have occured in the hall. Events include the trial of Charles I, the deposition of Richard II, the coronation banquet of Henry VIII, and many more!

3. A library straight out of Harry Potter

Imagine a cathedral filled with books and you'll probably be thinking of something like the John Rylands Library. Here you’ll find some of the rarest and most beautiful books in Britain including the oldest existing piece of the New Testament, the first edition of Chaucer’s The Canterbury Tales, the first editions of Dickens' novels still in their original wrappers, and a first edition of Shakespeare’s Sonnets. Overall, the Library is an impressive place well worth exploring.

Entry is free and you should be sure to take a look at the upcoming exhibitions calendar. You'll find more information on the John Rylands Library website.

Outside, George Gilbert Scott’s masterpiece looks a little like a castle in a fairytale, or a set from Harry Potter (unsurprising then, that the building did make a cameo appearance in one of the films, along with many other Harry Potter locations). With pointed spires soaring up alongside its great clocktower and crenelated walls bedecked with gargoyles – it gives a touch of magic to the more functional buildings that surround it.

Inside, it’s an explosion of colour and pattern that wouldn’t seem out of place in an Elizabethan palace. Ceilings painted with sky and stars, finely patterned carpets, grand staircases, and lavish bar areas.

5. A Victorian gothic fantasy castle

Despite being built in the 11th century, Cardiff Castle’s interiors are not the pragmatic medieval fortress interiors you’d expect. This is because during the Victorian times, architect and Medieval revivalist William Burges was given the freedom to explore his fascination with gothic and romantic styles by his patron, the 3rd Marquess of Bute. Today, it's almost a portfolio of Burges' creative abilties and as a result you’ll find some of the most opulent and diverse rooms you’re ever likely to see.

By far the most impressive is the Arab Room, a spectacular Moorish-style fantasy and a feat of design held to be among Burges' finest achievements. Sadly, he died before it was completed, but he's honoured with a Latin inscription inside.